The economic doldrums are having a hard time sullying the teflon-coated sales numbers of Holden Special Vehicles, the division that serves the same purpose within Holden that AMG does within Mercedes-Benz. Despite a slump in purchases of large sedans that has affected General Motors' standard Holden Commodore and savaged the Ford Falcon, the pricier and thirstier HSV models are, according to the division's CEO Phil Harding, doing fully 20 percent of Ford Falcon sales. Note, that's not 20 percent